Cumulative loneliness and subsequent memory function and rate of decline among adults aged ≥50 in the United States, 1996 to 2016

INTRODUCTION: The study objective was to investigate the association between loneliness duration and memory function over a 20-year period. METHODS: Data were from 9032 adults aged ≥50 in the Health and Retirement Study. Loneliness status (yes vs. no) was assessed biennially from 1996 to 2004 and its duration was categorized as never, 1 time point, 2 time points, and ≥3 time points. Episodic memory was assessed from 2004 to 2016 as a composite of immediate and delayed recall trials combined with proxy-reported memory. Mixed-effects linear regression models were fitted. RESULTS: A longer duration of loneliness was associated with lower memory scores (P < 0.001) and a faster rate of decline (P < 0.001). The association was stronger among adults aged ≥65 than those aged <65 (three-way interaction P = 0.013) and was stronger among women than men (three-way interaction P = 0.002). DISCUSSION: Cumulative loneliness may be a salient risk factor for accelerated memory aging, especially among women aged ≥65. HIGHLIGHT: A longer duration of loneliness was associated with accelerated memory aging. The association was stronger among women than men and among older adults than the younger. Reducing loneliness in mid- to late life may help maintain memory function.